Re: Enabling Checksums - Mailing list pgsql-hackers

From Jeff Davis
Subject Re: Enabling Checksums
Date
Msg-id 1352487218.6292.78.camel@jdavis-laptop
Whole thread Raw
In response to Re: Enabling Checksums  (Markus Wanner <markus@bluegap.ch>)
Responses Re: Enabling Checksums
List pgsql-hackers
On Fri, 2012-11-09 at 15:42 +0100, Markus Wanner wrote:
> On 11/09/2012 06:18 AM, Jesper Krogh wrote:
> > I would definately stuff our system in state = 2 in your
> > description if it was available.
> 
> Hm.. that's an interesting statement.
> 
> What's probably worst when switching from OFF to ON is the VACUUM run
> that needs to touch every page (provided you haven't ever turned
> checksumming on before). Maybe you want to save that step and still get
> the additional safety for newly dirtied pages, right?
> 
> A use case worth supporting?

One problem is telling which pages are protected and which aren't. We
can have a couple bits in the header indicating that a checksum is
present, but it's a little disappointing to have only a few bits
protecting a 16-bit checksum.

Also, I think that people will want to have a way to protect their old
data somehow.

Regards,Jeff Davis




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